Liquid-cooled lamp



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, LIQUID-9001.111) LAMP Filed 05. 22, 1941 2 sheets-sheet 1 lhvervtof:Cornelis Bot His Afiovneg.

Feb. 23, 19430 c. BOL 2,332,232

LIQUID-COOLED LAMP Filed Dec. 22 1941 2 Sheets-Sheet 2 lnven'tov ConelisBoL, b

Hi5 A'H'm- PH 3 Patented Feb. 23, 1943 LIQUID- CO OLED LAMP .CornelisB01, Palo Alto, .Calif., assignor to General Electric Company,

York

a corporation of New Application December 22, 1941, Serial No. 423,871

s Claims. (01. Moe-11.4)

My invention relates to an electric light projection device andmoreparticularly to a liquidcooled light generating device in which thelightsource is constituted by one or more highressure high-intensitymetal-vapor discharge lamps of the capillary type .disclosed and claimedin U. S. Patent No. 2,094,694, B01 et al., issued Octoher 5, 1937. v

High-pressure mercury lamps of the capillary type disclosed in the abovementioned patent employ a very small quartz tube, which may have a borediameter of the order of 2 mm. or so, as the enclosing envelope. Suchlamps are designed to be operated at relatively high wattage inputs,such as, for instance, 500 watts and above. higher wattage capillarylamps, such as those operating at 1000 watts and higher, it was foundthat in order to effectively dissipate such a great amount of energywithin such a small volume and thereby prevent overheating and softeningof the quartz tube, it was necessary to provide vigorous cooling of thelamp, aszby water or other liquid circulated over the surface of thequartz tube.

One object of my invention is to provide a liquid-cooled mountingarrangement for a highwattage tubular discharge lamp which willeffectively cool the lamp so as to prevent overheating thereof withresultant damage thereto.

Another object of my invention is to provide a liquid-cooled mountingarrangement for such high-wattage tubular discharge lamps which issimple in construction and which permits ready removal and replacementof the lamp.

Still another object of my invention is to provide a liquid-cooledmounting arrangement for high-wattage tubular discharge lamps in whicheach lamp is equipped with a surrounding glass With the tube serving asa jacket therefor, the lamp and the surrounding tube being permanentlyfastened together so as to form an integral unit which may bereadilyinserted and removed from the mounting device.

A still further object of my invention is to provide a liquid-cooledmounting arrangement for high-wattage tubular discharge lamps having ahollow reflector disposed externally of the lampjacketed portion of thedevice and extending closely adjacent the same, the reflector beingsubstantially co-extensive with the arc discharge in the lamp and havingits hollow interior in communication with the cooling liquid chambersurrounding the lamp so that the cooling liquid also circulates throughthe reflector to thereby prevent excessive heating and resultantdeterioration of the reflecting surface or coating there- Furtherobjects and advantages of my invention will appear from the followingdescription of a species thereof and from the accompanying drawings inwhich:

Fig. 1 is an elevation of an electric light generating device comprisingmy invention on a reduced scale; Fig. 2 is a longitudinal medial sectionof one of the similar sides or halves of the device shown in Fig. 1;Fig. 3 is a detail View of one of the lamp units' of the device shown inFig. 1; Fig. 4 is a transverse section taken on the line 4. 4 of Fig. 2;Fig. 5 is a transverse section taken on t'he line 5-5 of Fig. 2; Fig. 0is a transverse section taken on the line 5-,fi of Fig. 2; and Fig. 7 isa diagrammatic illustration showing the manner in which the lightgenerating device'a ccording to the invention is arranged with respectto a trough reflector to thereby form a light projection devicefor theprojection of an extremely powerful fan-shaped beam of light.

Referring torthe drawings, the lamp mounting arrangement there showncomprises an elongated base member ID, preferably in the form of aninverted chanel iron. Mounted above the base or channel member 10 andextending longitudinally on t c al porti the eof is an l at d hollowreflector member i 1 preferably made from sheet brass and coated with asuitable reflecting material, such as silver of chromium. The reflectormember is supported on, and spaced from the Web I2 of the channel l0, bysuitable support or spacer rings It. At its opposite ends, the reflectormember ll is'provided with an externally threaded outlet tube or conduitis threaded into the reflector so as to communicate with the hollowinterior thereof and extending down through an opening in the web I2 ofthe channel member I0. A nut 15, threaded onto each outlet pipe orconduit [4, engages the under surface of the channel web l2 so as tofirmly clamp the reflector member II and the spacer rings l3 against the'web I2 of the base member .10. At a point substantially midway betweenits ends, the reflector member H is further secured to the base [0 bymeans of an externally threaded inlet tube or conduit 16 threaded intothe reflector and extending down through an Opening in the channel Web|2 ,.-anda nut I 5 threaded onto the inlet pipe or conduit, l6 againstthe under surface of the channel web 12. The inlet pipe 16 extends upthrough the hollow reflector member H so as to project from the topsurface thereof, and accordingly is not in direct communication with thehollow interior of the reflector member. At their loweror free ends, theinlet and outlet pipes I 6 and 14 respectively, are each provided withsuitable coupling elements I! for connecting the pipes to the inlet and.outlet hose connections (not shown) for the cooling liquid to becirculated through the device.

Mounted centrally on the reflector member I! and fitting over the upperprojecting end of the inlet pipe I6 is a central lamp supporting memberor block l8 having a horizontal bore |9 extending therethroughlongitudinally of the base member ID. The said central support member I8is also provided with a second or vertical bore 29 extending at rightangles to, and communicating with the longitudinal bore l9, into whichbore the inlet tube I6 is threaded. The opposite ends of thelongitudinal bore l9 at each side of the hollow support member |8 areenlarged, as indicated at 2|, to form outlet chambers for the receptionof the inner end portions of longitudinally extending cylindrical outerjackets or tubes 22 of suitable light-transmitting material, such asglass or quartz. Each of the enlarged recesses or outlet chambers 2| inthe hollow supuort member l8 communicates with the hollow interior ofthe reflector member through the medium of a vertical slot or passageway23, formed in the hollow support member |8 on each side of the verticalbore 20, and aligned slots 24 in the upper wall of the reflector membeI, the said slots 23 being located at the innermost portions of theenlarged recesses 2|.

Each outer jacket or tube 22 is concentrically mounted within theenlarged bore portion 2| of the support member l8, and is secured inplace in the said member l8 by means of a rubber washer 25 surroundingthe said tube and compressed against an annular shoulder 26 in the boreportion 2| by an annular compression or looking ring 21 threaded intothe bore portion 2|. The compression of the rubber washer 25 by the ring21 squeezes the washer against the outer jacket or tube 22 so as tosecurely hold the tube in place within the support member I8 and at thesame time provide a liquid-tight seal therebetween, The outer jackets 22are mounted in the support member l8 with their innermost ends spaced aslight distance rom the annular shoulders 28 formed in the bore l9 bythe enlarged portions 2| thereof. In this manner, sufiicient clearanceor passageway is provided for the flow of the cooling liquid from theouter jackets 22 into the enlarged bore portions or outlet chambers 2|and thence through the slots 23 and the openings 24 into the hollowreflector member l.

The outer end of each outer jacket or tube 22 is mounted in an endsupport sleeve 29 which is supported on a suitable insulator 39 boltedor otherwise fastened to the base member I0, the sleeve 29 being securedto the insulator by suitable means, such as a clamp member 3| suitablyfastened to the insulator as by a bolt 32. The inner end of the sleeve29 is formed with an enlarged portion 33 having an enlarged bore 34within which the outer end of the jacket 22 is received. The outerjacket or tube 22 is concentrically mounted and secured in place withinthe sleeve 29 by means of a rubber washer 35 which is compressed by acompression ring 36 against the annular shoulder 31 formed in the sleeveby the enlarged bore portion 34, the compression ring 36 threading intothe enlarged bore 34 in the sleeve to thereby compress the rubberwasher. As in the case of the rubber washer 25 at the shown moreparticularly in Fig. 3. The lamp unit is readily removable through theouter end of the outer jacket 22 and comprises an inner jacket orvelocity tube 39 of suitable light-transmitting material, such as glassor quartz, and a high- 3 pressure mercury lamp of the capillary typedescribed and claimed in the above mentioned I U. S. Patent No.2,094,694 of B01 et al., the lamp inner end of the tube 22, thecompression of the 49 being mounted concentrically within the velocitytube 39 adjacent the inner end thereof. The formation of the velocitytube 39 and the capillary lamp 40 as a single unit permits the easyassembly of such parts in the device and therefore the easy replacementthereof. With the lamp unit 38 in place within the outer jacket 22, thevelocity tube 39 and outer jacket 22 surrounding the lamp 40 form, ineffect, a jacket structure therefor.

The inner end of the velocity tube 39 is provided with an inner metalcap 4|, preferably of brass, which is cemented or otherwise secured tothe velocity tube 39 and which fits into the longitudinal bore |9 in thecentral support member l8 to thereby support the inner end of the lampunit. An annular shoulder 42 formed in the central support member |8within the bore |9 provides an abutment or stop against which the metalcap 4| seats to limit the inward movement of the lamp unit into, andproperly position the inner end of the lamp unit in, the central supportmember H3. The engagement of the inner end caps 4| of the two lamp units38 with the annular abutment shoulders 42 in the support member I8serves to close off or separate the inner or reduced diameter portion ofthe bore |9 from the enlarged outer portions 2| thereof so as to form,in effect, an inlet chamber in said support member.

The metal cap 4| is provided with a suitable lamp socket comprising aplurality (preferably four) of spring fingers 43 extending inwardly fromthe end wall 44 of the cap into the velocity tube 39 and resilientlyengaging the metal lamp base or terminal 45 at the inner end of thecapillary lamp 49 to thereby support the lamp at said end andelectrically connect the metal cap 4| to the said base 45. Such aspring-finger socket arrangement permits the lamp base 45 to slidetherein thus relieving the lamp of any strain which might otherwiseresult from the expansion and consequent elongation of the lamp duringthe operation thereof. The end wall 44 of the metal cap 4| is providedwith a plurality of inlet openings 46 therethrough preferably ofcircular form and communicating with the interior of the inner jacket orvelocity tube 39, the openings 46 being arranged preferably in a circleabout,

the lamp socket 43 and being of sufiicient size to provide sufficientpassageway for the free flow of adequate cooling liquid therethroughinto the velocity tube 39.

The outer end of the lamp 49 is supported by means of a glass supporttube 41 disposed concentrically within the velocity tube 39 andenclosing the seal portion 48 of the lamp at the said outer end thereof;a rubber sleeve 49 fitting over the said lamp seal portion 48 and beingcompressed between the said seal portion and the enclosing glass supporttube 41 to thereby form a liquid-tight seal therebetween. A rubberwasher 50, fitting over the glass support tube 44 and resting against aflange or enlargement 5| formed on the support tube 41 at a pointintermediate the outer end 48 of the lamp and the outer end of thejacket or velocity tube 39, serves to support and more or less centerthe support tube 4.1 within the velocity tube 39. The support tube isfurther held in position within the velocity tube 39 by means of afilling 52 of a suitable insulating compound which completely fills theglass support tube 41 as well as the outer end of the jacket or tube 39up to the rubber washer 50, the latter thus serving as a retainingmember for confining the filling compound 52 to that portion of thejacket 39 outwardly of the rubber washer. The filling compound 52provides a liquid-tight seal between the lamp support tube 4'! and thevelocity tube 39 so as to prevent leakage of the cooling liquid out ofthe outer end of the lamp unit.

A metal cap 53, fitting over the outer end of the velocity tube 39,closes the outer end of the lamp unit 38 and forms the outer terminaltherefor. The outer cap 53 is held in place on the end of the velocitytube 39, and is electrically connected to the tungsten leading-in wire54 of the lamp at the outer end 48 thereof, by means of a connectingwire 55 soldered or otherwise secured to the outer cap 53.

At a point approximately opposite the outer end of the effectivelight-producing extent of the lamp 49, the surrounding jacket orvelocity tube 39 is provided with a plurality of outlet openings 56 inthe wall thereof through which openings the cooling liquid flows out ofthe inner jacket 39 into the outer jacket 22. As'in the case of theinlet openings 46 in the metal inner cap 4| at the inner end of the lampunit, the outlet openings 56 should together provide adequate passagewayfor the free flow of the cooling liquid therethrough. However, eachindividual opening 56 should be small enough to trap the larger-sizedbroken quartz parts of the lamp should the latter break, thus preventingsuch broken glass parts from passing into the cooling liquid system.

Each lamp unit 38 is supported adjacent its outer end by means of arubber sleeve which is compressed against the outer end of the supportsleeve 29 and against the wall of the inner jacket or velocity tube 39by a cap nut 58 fitting over the velocity tube 39 and threaded onto thesupport sleeve 29, the compressed rubber sleeve 57 thus serving also toprovide a liquid-tight seal between the velocity tube 39 and the supportsleeve 29. It will be evident from the above that the various elementsconstituting the support for the outer end of the lamp unit 38 areentirely. insulated from both sides of the power supply to the lamp soas to be under no potential whatever, thus avoiding power lossesthereat.

To prevent the lamp units 38 from being ejected. or blown out of thetubes 22 through the open outer ends of the sleeves 29 by the pressureof the cooling liquid therein, suitable stop members in the form ofcylindrical metal blocks or contacts 59 are provided, the said stopmembers 59 being slidably mounted in suitable clamp members 69 havingclamping bolts 6| and fastened in a suitable manner, as by bolts 62, toinsulators 63, bolted or otherwise secured to the base member l9.Connector lugs 64 provided with binding screws 65 are clamped betweenthe insulators 63 and the clamp members 60 and provide a suitable meansfor connecting the current supply Wires from one side of the line to thedevice so as to be electrically connected through is made through thecentral support member l8, $51

against which the inner end terminal rests, and through the frame orbase III of the device, the current supply wires from the other side ofthe line being connected to a suitable part of the frame or base I!) ofthe device, or to a related member.

. As shown particularly in Fig. 6, the upper wall 66 of the hollowreflector II is so shaped in transverse cross-section as to present aconcave reflecting surface facing the lamps 40 and symmetricaltherewith. The reflecting surface may be of any suitable shape, but ispreferably formed of two halves 61, 68 each of circular cross-sectionwith their axes of curvature 61., 68' (Fig. 7) parallel to but displaceda slight distance to one side of the longitudinal center line of thelamp; i. e., to that side on which the corresponding half-section lies,so that the reflected rays of light from the reflector will not passthrough the discharge space within the lamp but instead will form images69 slightly to one side thereof. In this manner the limit on the energyinput of the lamp which is set where the reflected images of the lampdischarge are allowed to form in the discharge itself, is entirelyobviated. The axes of curvature 61', 68 of the two circular reflectingsurfaces 61, 68 are preferably displaced to one side of the lamp adistance such that the reflected images 69 of the light source areformed outside of the lamp 40 but inside of the inner jacket or velocitytube 39, as shown in Fig. 7.

To strengthen the upper wall 66 of the reflector ll, centrally arrangedlongitudinal reinforcing ribs or webs 1'9 are provided within. thehollow reflector between the upper and lower walls thereof. Midway ofits length, the reflector ll is provided with transverse baflie membersor partitions N (Fig. 4) disposed within the reflector on opposite sidesof the inlet tube l6 passing therethrough, the said ballle platesdividing the reflector into two separate sections or compartments sothat the cooling liquid entering each section will flow therethrough inone direction only and with a regular flow.

The capillary lamps 40 employed have an inside diameter of approximately2 mm. and an outside diameter of approximately 6 mm., and have adischarge gap of approximately mm. The lamp exhaust tube tip 12 islocated closely adjacent one end of the lamp and inclined toward suchend; and each lamp is mounted in its corresponding velocity tube 39 sothat the inclination of the exhaust tube tip 12 is in the direction of,and does not interfere with the flow of the cooling liquid as it passesthrough the velocity tube. The lamps are designed to operate at aninternal pressure above 70 atmospheres with an operating voltage ofabout 6,000 volts and an operating current of about 1.3 to 1.5 amperes.The supply circuit should have an open circuit voltage of about 9,300volts and a short circuit current of approximately 2.5 amperes. Duringoperation, the lamps 49 emit light in an amount approximating 65 lumensper watt. The lamps are operated from a suitable step-up transformer,the outer end terminals 53 of the lamps being connected to the oppositeends of the transformer secondary and the inner end terminals 45 of thelamps being connected to a grounded center tap of the secondary." Theprimary of the transformer is connected to a 220-volt source of current.

As shown in Fig. 7, the lighting unit according to the inventionispreferably used in conjunction with a relatively large trough-shapedreflector I3 of paraboloidal shape to thereby provide a wide fan-shapedbeam of light of exceptionally high intensity and. especially suitablefor airport lighting and other similar purposes, the unit being mountedwith the lamps 40 extending along the focal axis of the main reflectorI3 and with its reflecting surfaces 61, 68 facing the main reflector I3so that the light reflected by such surfaces is directed onto the mainreflector.

To operate the lighting unit, the inlet and outlet pipes I4 and I6 arejoined by the couplings I! to the inlet, and outlet hose connections ofthe cooling liquid system, and the cooling liquid circulated underpressure through the device. As shown by the arrows in Fig. 2, thecooling liquid from the inlet pipe I6 first enters the longitudinal boreI9 in the central support member I8, then enters the velocity tubes 39of the two lamp units, through the inlet openings 46 in the inner endcaps 4| thereof, and flows along the lamps 40 so as to effectively coolthe same. The cooling liquid in each lamp unit then flows out of thevelocity tube 39, through the outlet openings 56 therein, into the outerjacket 22 through which it then flows in a direction opposite to that ofthe flow in the velocity tube 39. The cooling liquid flows out of theopen inner end of the outer jacket 22 into the enlarged portion 2I ofthe longitudinal bore in the central support member I8, and then passesthrough the aligned slots 23, 24 in the said support member and thereflector l l into one section of the said reflector through which itthen flows in one direction only towards the outlet end of suchreflector section, the cooling liquid leaving the reflector through theoutlet pipe I4 connected thereto.

After the flow of cooling liquid through the device has once beeninitiated, the electrical circuit through the lamps 49 may be thenenergized so as to start the operation of the lamps. The heat thereaftergenerated by the discharge within the lamps is then dissipated by thecooling liquid continually circulating through the device, so that thesaid device is thus effectively cooled at all times during its operationand softening of the quartz lamp tubes prevented. The circulation of thecooling liquid through the reflector I I serves to cool the same and soprevent the deterioration of the reflecting coating thereon by the heatdeveloped by the discharge in the lamps.

When it is desired to stop the operation of the device, the lamps, 40are first de-energized and then the flow of cooling liquid through thedevice interrupted. In this way, continuous cooling of the device isassured throughout the entire period of lamp operation, right up to thetime lamp operation ceases.

Where it is desired to prevent ultraviolet rays from leaving the device,the velocity tube 39 or the outer jacket 22, or both, may be made of aglass which will absorb the ultraviolet rays, such as a soft glass, forinstance. Preferably, however, the velocity tube and the outer jacketare made of a suitable hard glass, such as Pyrex o-r Nonex, whichtransmits the visible rays of the spectrum as well as the higherwave-length ultraviolet.

Where the transmission of all the ultraviolet as well as the visiblerays of the spectrum is desired, both the velocity tube 39 and the outerjacket 22 are made of quartz. However, where the transmission of onlythe ultraviolet is wanted, then the velocity tube 39, and if desired theouter jacket 22 as well, may be made of a glass which absorbs thevisible light but transmits the ultraviolet rays, such as, for instance.red Uviol glass or that commercially known as Red Purple Ultra glass.The velocity tube 39 in such case serves as a filter to absorb all thevisible light, and such absorption therefore results in the heating upof the velocity tube. However, the cooling of both sides of the velocitytube 39 by the cooling liquid circulating through the device insures theadequate cooling of such tube so as to prevent any damage thereto fromexcessive heating. of the same.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A liquid-cooled mounting device for a high intensity tubular electriclamp comprising a cooling-liquid jacket structure including a tubularouter jacket of material permeable to radiations of the lamp and atubular inner jacket of material permeable to radiations of the lampdisposed within said outer jacket and spaced therefrom so as to providean outer cooling chamber therebetween, a support member for one end ofsaid tubular jacket structure, said support member being provided withinlet and outlet chambers separate from one another, the ends of saidinner and outer jackets supported by said support member being open andin communication respectively with the said inlet and outlet chambers insaid support member, and closure means for closing said inner and outerjackets at the ends thereof opposite from those ends supported by saidsupport member, said inner jacket being formed with an opening in thewall thereof at a point intermediate its ends to thereby providecommunication between the interior of said inner jacket and the saidouter cooling chamber.

2. A liquid-cooled mounting device for a high intensity tubular electriclamp comprising a tubular outer jacket of material permeable toradiations of the lamp, a support member for one end of said outerjacket, said support member having inlet and outlet chambers separatefrom one another and the said supported end of said outer jacket beingin communication with said outlet chamber, a removable lamp unitdisposed within said outer jacket and removable therefrom,-said lampunit comprising an inner jacket of material permeable to radiations ofthe lamp and spaced from said outer jacket so as to provide an outercooling chamber therebetween, and support means within said inner jacketfor supporting the said lamp therein and in spaced relation thereto soas to provide an inner cooling chamber, one end of said inner jacketbeing closed and the other end thereof being supported by said supportmember and in communication with the said inlet chamber therein, saidinner jacket being formed with an opening in the wall thereof as a pointintermediate its ends to thereby provide communication between saidinner and outer cooling chambers, and closure means for closing that endof the said outer cooling chamber remote from said support member.

. 3. A liquid-cooledmounting device for a highintensity tubular electricla'mp comprising a support member having a hollow interior with inletand outlet passageways in communication therewith, a readily removabletubular lamp unit having one end extending into the hollow interior ofsaid support member and supported thereby so as to divide the saidhollow interior into two separate chambers with the supported end ofsaid lamp unit in communication with one of said chambers, an outerjacket of material permeable to radiations of the lamp and. surroundingsaid lamp unit so as to provide an outer cooling chamber therebetween,said outer jacket also having one end thereof extending into the hollowinterior of said support member and supported thereby with the supportedend of said outer jacket in communication with the other of saidchambers in said support member, said lamp unit comprising a tubularinner jacket of material permeable to radiations of the lamp and supportmeans in said inner jacket for supporting the said lamp therein and inspaced relation thereto so as to form an inner cooling chambertherebetween, the end of said inner jacket opposite that end thereofsupported in said support member being closed, said inner jacket beingformed with an opening in the wall thereof at a point intermediate itsends to thereby provide intercommunication between said inner and outercooling charmbers, and closure means for closing that end of the saidouter cooling chamber remote from said support member.

4. A liquid-cooled mounting device for a highintensity tubular electriclamp comprising an elongated base member having inlet and outletconduits for the cooling liquid, a hollow support member secured to saidbase member and having an inlet chamber in communication with the saidinlet conduit in said base member, said support member also having anoutlet chamber, a tubular cooling-liquid jacket structure for said lampmounted on said base member and supported at one end by said hollowsupport member, said jacket structure having an inlet opening incommunication with the said inlet chamber in said support member and anoutlet opening in communication with the said outlet chamber in saidsupport member, and an elongated hollow reflector member mounted on saidbase member externally of said jacket structure and extendinglongitudinally thereof and closely adjacent thereto, said support memberhaving a passageway connecting the said outlet chamber therein with thehollow interior of said reflector member.

5. A liquid-cooled mounting device for a highintensity tubular electriclamp comprising a base member having inlet and outlet conduits for thecooling liquid, a hollow support member secured to said base member andhaving passageways communicating with said inlet and outlet conduits, atubular open ended outer jacket of material permeable to radiations ofthe lamp and having one end thereof supported by said hollow supportmember and in communication with one of said passageways therein, atubular lamp unit disposed within said outer jacket and spaced therefromso as to provide an outer cooling chamber therebetween, said lamp unitcomprising a tubular inner jacket of material permeable to radiations ofthe lamp with the said electric lamp mounted longitudinally therein andspaced therefrom so as to provide an inner cooling chamber, said innerjacket being closed at one end and having its other end supported bysaid hollow support member and communicating with the other of saidpassageways therein, said inner jacket being also formed with an openingin the wall thereof intermediate its ends so as to provideintercommunication between said inner and outer cooling chambers, andsealing means between said outer and inner jackets for closing the saidouter cooling chamber at that end thereoi remote from said hollowsupport member,

6. A liquid-cooled mounting device for supporting a plurality of highintensity tubular lamps in end to end relation comprising a commonsupport member for supporting the adjacent ends of said lamps, saidsupport'member having a common inlet chamber and a plurality of outletchambers, and a plurality of cooling-liquid jacket structures for saidlamps, one for each lamp, each of said jacket structures being supportedat their inner ends in said common support member and having an inletopening in communication with the said common inlet chamber in saidsupport member and an outlet opening in communication with one of saidoutlet chambers in said support member.

'7. A liquid-cooled mounting device for a plurality of high intensitytubular electric lamps comprising a common support member for supportingthe inner end of each of the lamps, said support member having a hollowinterior with inlet and outlet passageways in communication therewith, aplurality of readily removable tubular lamp units each having its innerend extending into the hollow interior of said common support member andsupported thereby so as to divide the said hollow interior into a commoninlet chamber and a plurality of outlet chambers separate from saidinlet chamber with the said inner ends of the lamp units incommunication with said inlet chamber, a plurality of outer jackets ofmaterial permeable to radiations of the said lamps and each surroundingone of said lamp units so as to provide outer cooling chamberstherebetween, each of said outer jackets having its inner end extendinginto the hollow interior of said support member and supported therebywith the inner end of each of said outer jackets in communication withone of said outlet chambers in said common support member, each of saidlamp units comprising a tubular inner jacket of material pervious toradiations of the said lamps and support means in said inner jackets forsupporting one of said lamps therein and in spaced relation thereto soas to form an inner cooling chamber therebetween, the outer ends of saidinner jackets being closed, said inner jackets being formed withopenings in the walls thereof at points intermediate their ends tothereby provide intercommunication between said inner and outer coolingchambers, and closure means for closing the outer end of said outercooling chamber.

8. A replaceable lamp unit for a liquid-cooled light generating devicecomprising a high intensity tubular electric lamp, a tubular jacketsurrounding said lamp and spaced therefrom so as to provide a coolingchamber therebetween, said jacket being made of a material permeable toradiations of said lamp, support means at one end of said jacket forsupporting one end of said lamp and for closing the said end of saidjacket to thereby render the same liquid-tight, and terminal means atthe other end of said jacket for supporting the other end of said lampand providing a terminal therefor, said terminal means having an openingtherethrough providing a passageway into the said cooling chamber andsaid outer jacket having an opening in the wall thereof at a pointintermediate its ends to provide a second passageway into the saidcooling chamber.

CORNELIS BOL.

